Have Passive Preamps Finally Come of Age?


Back in the late 90s (eons ago) I tried a variety of passive preamps (PPs). The most musical was an autoformer, but back then my system was not balanced. For the last decade I have been using active preamps, both tube and solid state, but finding a quality balanced preamp under $4K is damn near impossible. Enter the Parasound P5 (2.1), which in addition to having balanced I/Os, it has a separate bass management circuit (MSRP $1095), and I was hoping it would provide better control over the built in class D plates incorporated into my 2 SVS powered subs, whose volume controls are STUPIDLY sensitive: when barely cracked from zero they overwhelm. Alas, no bueno. 

Recently i watched a PS Audio YT video that was emphatic about NOT connecting powered subs with interconnects; instead he recommends speaker cables piggybacked off the main systems amp/s. I had a spare set of DIY flat copper cables, and was shocked how much better they sounded, but doing so did not change the  volume control problem and unfortunately this id not bypass the SVS amps whose class D chips are now ancient. Thinking there could be an impedance problem led me to revisit PPs.

I sold my P5 and was using the XLR outs from my Oppo 105 (upgraded power supply and IEC/wiring to the power supply) direct to my Emerald Physics 100.2SEs (class D). The noise floor dropped tremendously, allowing me a much better view into the music. My Core Power Technologies 1800 PLC had more than a little to do with this, but...  

Days of PP research later, I came across LDRs, which seem like the ultimate PP option, but XLR versions are ~ $2K and up, with the Tortuga coming in at $2700, seems like a true SOTA bargain, just not in my current budget. Scouring the' for sale' sites I came across a Hattor XLR (MSRP $995) which was in my price range. Hattor's www had links to 2 reviews both were extremely positive: one used it in combination with a class D amp. Bingo! I snapped it up.

It arrived late yesterday, although Hattor's www pictures look awesome, they do not compare to seeing and touching it. The metal carrying case was an indication of the designer's dedication. This is an etremely well made piece of kit, but how does it sound? Alas it came with no manual and Hattor's site does not have a PDF. How hard can it be to hook up? Well, after a couple scary minutes, I discovered that it would not light up until I connected the 105. 

Stone cold, the first thing that shocked me was a further reduction in noise floor and an incredibly wide and deep sound stage, but as can be expected, it was dry. Fingers crossed, in about a half hour I began to be rewarded with texture as well. Tis only got better as the night wore on

I hope somebody chimes in with their Tortuga experience, or any other high quality PP information.that goes under the reporting radar. 
tweak1
Well, I have been living with my Luminous Audio Axiom II for a week now. It is the top single ended unit : Walker mod, 3 in, 2 out, with remote. I can honestly say I have reached a point where I am hearing " everything " within the recordings. I can better connect with the artistry of the musicians and, the work of the recording and mastering engineers. It is an open window, unaltered, allowing me to hear it all as I believe it should be. I will report further as time goes on, but so far, I am very lucky with the synergy, and even happier with the outcome. Enjoy ! MrD.
tweak1 OP
My EP KC IIs sound fantastic

Actually hate to say, your Emerald Phyics EP-100.2SE Class-D amps are not a great match for a passive pre, as their input impedance is "not typical" as they are very low at 19kohm, your passive preamp while working fine would sound even better if it had a unity gain buffer on it’s output.
For a 10kohm passive to work it’s magic the input impedance of an amp/s should be 33kohm or higher.

Cheers George
Thanks George. While the combo sounds vg, there is something eating at me. Not sure whether it's the amps or the speakers. I own EP  KCIIs, but bought a pair  of demo EP 3.0s Alas, there have been weird issues involved in them being delivered. I have been keen on getting a Nord Two Stereo amp, but need to sell at least one SE first
Hi tweak1,
I`ve been using the Tortuga LDR for awhile now and I`m enjoying it very much.

I added an inexpensive tube buffer (Yaqin CD-3) to help with impedance matching after pulling out my Rogue Tube amp and putting in an ATI SS amp in its place.

I did it for fun, as I absolutely loved the Rogue and it has been a stellar performer. 
I listen at a lowish volume level but  I just wanted to hear what a hefty amp would do for my Revels.
The Tortuga, Yaqin combo sounds very clean and clear and the front panel volume display numbers on the LDR have dropped quite a bit which seems to show everything is playing nicely together...very please !!